One of the most common knee injuries is an anterior cruciate ligament sprain or tear.
Athletes who participate in high demand sports like soccer, football, and basketball are more likely to injure their anterior cruciate ligaments.
Grade 1 Sprains. The ligament is mildly damaged in a Grade 1 Sprain. It has been slightly stretched, but is still able to help keep the knee joint stable.
Grade 2 Sprains. A Grade 2 Sprain stretches the ligament to the point where it becomes loose. This is often referred to as a partial tear of the ligament.
Grade 3 Sprains. This type of sprain is most commonly referred to as a complete tear of the ligament. The ligament has been split into two pieces, and the knee joint is unstable.
Partial tears of the anterior cruciate ligament are rare; most ACL injuries are complete or near complete tears.